1. Technical Field of the Invention
The present invention relates to a method of encoding and decoding motion picture, a motion picture encoding device, and a motion picture decoding device.
2. Related Art
Conventional techniques of this type are known as H.261, H.263, MPEG-1, MPEG-2, MPEG-4, etc. Many techniques of motion picture coding including those cited are to perform key frame coding and motion vector estimation in units of blocks, the location and size of which are fixed. MPEG-4 allows the use of four vectors, but basically the vectors are used to just divide the blocks (for example, see Patent Document 1).
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-287212 (FIG. 1 and Paragraph Nos. [0007] to [0015]).
In the case of the block-based encoding, if the amount of coding is insufficient or motion vector estimation ended in failure, it will cause a strong discontinuity on the boundary of blocks, so-called block distortion. The accuracy of motion vector estimation itself is also in question. In other words, since motion estimation is always performed in units of fixed-size blocks, if two or more objects are in motion in a block, right motion vectors may not be able to be determined. Even if a dominant motion vector is estimated correctly, the texture of an object originally having another motion vector in the block may be affected by the dominant motion vector. In this case, if the affected motion vector is used for motion compensation, a motion distortion may be caused.